A new report has been released today by Nuffield Australia: “Cover Crops – Nutrient use efficiency and fertiliser application methods”
Written by David Cook, Australian Nuffield Scholar from Pine Lodge, Victoria, its key points are that
Increasing soil organic carbon levels is essential to maintain high levels of agricultural production and can be used as an indicator of soil health.
Cover crops provide ground cover in a non-crop period and are one tool that can be used to increase soil organic carbon levels.
Multi species cover crops have added benefits compared to single species.
Our understanding of the biological interactions that occur in the soil between the microorganisms and the effect on plant growth and quality is very limited, but research is focusing on this all around the world.
As a major cost of growing crops, increasing nutrient use efficiency would have a significant effect of reducing fertiliser usage and costs, especially in respect to nitrogen.
The CULTAN (Controlled Uptake Long Term Ammonium Nutrition) system involves concentrated banding of nutrients in the soil. Work with nitrogen has shown nitrogen use efficiency of around 90%.
Building soil organic levels will be best achieved by incorporating as many favourable practices as possible – diverse crop rotation, no-till/stubble retention, cover crops and grazing management.
In just six years, Victorian farmer David Cook has gone from a tyne-based seeding system and burning stubbles to full stubble retention with a dedicated no-till disc seeder.
However, David was convinced he could evolve his system further, so he used a 2013 Nuffield Scholarship to investigate cover cropping, opportunistic summer crops and fertiliser use efficiency.
He says there was plenty of incentive for his research, including increasing organic carbon levels, improving soil health, better utilisation of fertiliser and integrated weed control.